The presence of undesired vegetation causes substantial damage to agricultural products which helps satisfy man's basic food and fiber needs. The current population explosion and concomitant world food and fiber shortage demand improved productivity in agricultural efforts since virtually all the readily available, relatively fertile cropland in developed countries has already been placed in use [Science 214, 1087, 1089 (1981)]. Preventing or minimizing loss of a portion of such valuable crops, by inhibiting the growth or killing undesired competing vegetation which is potentially most damaging to crop yields [Science 215, 134 (1982)], is a significant approach to improving agricultural efficiency.
A wide variety of materials, commonly referred to as herbicides, useful for controlling the growth of undesired vegetation (by killing or inhibiting) is available. There still exists a need, however, for effective herbicides which destroy or control weeds while not significantly damaging useful crops. Efficient production on large acreage requires the extensive use of herbicides used by American farmers in 1981 [Chemical Weed, July 7, 1982, p. 36]. At the present time, no existing product provides all features deemed advantageous. Greater persistence, less soil residual, reduced application rates, reduced soil binding, greater selectivity or safety margin between weed control and crop injury, and less dependence on rainfall for activation are currently desirable features for herbicides.
EP-A-13,480 published July 23, 1980, discloses hericidal sulfonamides of the formula ##STR1## wherein
R.sub.1 is H, Cl, Br, F, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkylthio, NO.sub.2 or CO.sub.2 R.sub.5.
U.S. Pat. No. 4,339,267 discloses herbicidal sulfonamides of the formula ##STR2## wherein
R.sub.4 is H, Cl, Br, F, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, NO.sub.2, CO.sub.2 R.sub.6 or SR.sub.13.
U.S. Pat. No. 4,342,587 discloses herbicidal sulfonamides of the formula ##STR3## wherein
B is Cl or Br.
U.S. Pat. No. 4,456,469 discloses herbicidal sulfonamides of the formula ##STR4## wherein
R is C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.6 alkenyl, C.sub.2 -C.sub.4 alkoxyalkyl, C.sub.5 -C.sub.6 cycloalkyl, R'OCH.sub.2 CH.sub.2 OCH.sub.2,
R'OCH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2, ##STR5## CF.sub.3 ,
CF.sub.3 CH.sub.2, HGLCCF.sub.2 or HCF.sub.2 ; and Z is H, F, Cl, Br, CH.sub.3, OCH.sub.3 or SCH.sub.3.
U.S. Pat. No. 4,487,626 discloses herbicidal sulfonamides of the formula ##STR6##
R.sub.2 is H, F, Cl, Br, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, NO.sub.2, CO.sub.2 R.sub.15, S(O).sub.m R.sub.16, SO.sub.2 NR.sub.18 R.sub.19 or SO.sub.2 N(OCH.sub.3)CH.sub.3.
U.S. Pat. No. 4,421,550 discloses herbicidal sulfonamides of the formula ##STR7## and
R.sub.16 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, F, Cl, Br, CF.sub.3, CO.sub.2 R.sub.20, SO.sub.2 NR.sub.10 R.sub.11, SO.sub.2 N(OCH.sub.3)CH.sub.3 or S(O).sub.n R.sub.13.
U.S. Pat. No. 4,496,392 discloses herbicidal sulfonamides of the formula ##STR8## wherein
R.sub.3 is Cl, SO.sub.2 CH.sub.3 or SO.sub.2 N(CH.sub.3).sub.2.
EP-A-84,224, published July 27, 1983, discloses herbicidal sulfonamides of the formula ##STR9##
R.sub.16 is H, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, F, Cl, Br, CF.sub.3, CO.sub.2 R.sub.9, SO.sub.2 NR.sub.10 R.sub.11, SO.sub.2 N(OCH.sub.3)CH.sub.3 or S(O).sub.n R.sub.13.
EP-A-125,846, published Nov. 21, 1984, discloses herbicidal sulfonamides of the formula ##STR10##
R.sub.3 is Cl, SO.sub.2 CH.sub.3, SO.sub.2 N(CH.sub.3).sub.2, OCH.sub.3, NO.sub.2 or N(CH.sub.3).sub.2.
EP-A-155,767, published Sept. 25, 1985, discloses hericidal sulfonamides of the formula ##STR11##
R.sub.5 is H, CH.sub.3, Cl, Br, CO.sub.2 R.sub.15, C(O)NR.sub.16 R.sub.17, SO.sub.2 NR.sub.16 R.sub.17, SO.sub.2 N(OCH.sub.3)CH.sub.3, SO.sub.2 R.sub.18 or NO.sub.2.
EP-A-161,905, published Nov. 21, 1985, discloses herbicidal sulfonamides of the formula ##STR12## wherein
R.sub.4 is CH.sub.3, CH.sub.2 CH.sub.3, OCH.sub.3, OCH.sub.2 CH.sub.3, F, Cl, Br, SO.sub.2 NR.sub.16 R.sub.17, SO.sub.2 N(OCH.sub.3)CH.sub.3, S(O).sub.n R.sub.19, C.sub.3 -C.sub.4 alkenyloxy or C.sub.3 -C.sub.4 alkynyloxy.
EP-A-164,269, published Dec. 11, 1985, discloses herbicidal sulfonamides of the formula ##STR13## wherein
R.sub.4 is CH.sub.3, CH.sub.2 CH.sub.3, OCH.sub.3, OCH.sub.2 CH.sub.3, F, Cl, Br, SO.sub.2 NR.sub.11 R.sub.12, SO.sub.2 N(OCH.sub.3)CH.sub.3 or S(O).sub.n R.sub.13.
EP-A-171,286, published Feb. 12, 1986, discloses herbicidal sulfonamides of the formula ##STR14## wherein
R.sub.4 is CH.sub.3, CH.sub.2 CH.sub.3, OCH.sub.3, OCH.sub.2 CH.sub.3, F, Cl, Br, SO.sub.2 NR.sub.18 R.sub.19, SO.sub.2 N(OCH.sub.3)CH.sub.3, S(O).sub.n R.sub.21, C.sub.3 -C.sub.4 alkenyloxy, CH.sub.2 OCH.sub.3 or CH.sub.2 OCH.sub.2 CH.sub.3.
EP-A-187,489, published July 16, 1986, discloses herbicidal sulfonamides of the formula ##STR15##
Q is an optionally substituted 3- or4-membered ring; and
W is substituted alkenyl or alkynyl.
AU-A-24259/84, published Sept. 6, 1984, discloses herbicidal quanidines of the formula ##STR16## wherein
R.sub.26 and R.sub.27 are independently H, F, Cl, Br, NO.sub.2, CN, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 haloalkoxy, C.sub.1 -C.sub.4 alkylthio, C.sub.1 -C.sub.4 haloalkylthio, C.sub.1 -C.sub.4 alkylsulfinyl, C.sub.1 -C.sub.4 haloalkylsulfinyl, C.sub.1 -C.sub.4 alkylsulfonyl, C.sub.1 -C.sub.4 haloalkylsulfonyl, di-(C.sub.1 -C.sub.4 alkyl)-aminosulfonyl or C.sub.1 -C.sub.4 alkoxy carbonyl.
EP-A-117,014, published Aug. 29, 1984, discloses herbicidal guanidines of the formula ##STR17## wherein
R.sub.8 is CH.sub.3, CH.sub.2 CH.sub.3, OCH.sub.3, OCH.sub.2 CH.sub.3, F, Cl, Br, SO.sub.2 NR.sub.20 R.sub.21, SO.sub.2 N(OCH.sub.3)CH.sub.3 or S(O).sub.n R.sub.23.
JAP 62-111,982, published May 22, 1987, discloses herbicidal pyridine sulfonylureas containing a ortho-CH.sub.2 OR.sub.1 group, wherein R.sub.1 is C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 haloalkyl.